[loh-es, les, luhs]


a loamy deposit formed by wind, usually yellowish and calcareous, common in the Mississippi Valley and in Europe and Asia.

Origin of loess

1825–35; < German Löss < Swiss German lösch loose, slack (sch taken as a dial. equivalent of German s), akin to German lose loose
Related formslo·ess·i·al, lo·ess·al, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for loess

Historical Examples of loess

  • A disadvantage of the loess lies in the readiness with which it washes.

  • By accenting the height of the ridges the loess also adds to the scenery of the county.

  • In Europe and in the Americas, accumulations of loess are generally from 20 to 30 meters thick.


    A. S. Walker

  • The thickest known deposit of loess, 335 meters, is on the Loess Plateau in China.


    A. S. Walker

  • Many thousands of square miles of northern China are covered with loess.


    William J. Miller

British Dictionary definitions for loess



a light-coloured fine-grained accumulation of clay and silt particles that have been deposited by the wind
Derived Formsloessial (ləʊˈɛsɪəl) or loessal, adjective

Word Origin for loess

C19: from German Löss, from Swiss German dialect lösch loose
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for loess

1833 (in Lyell), "unstratified deposit of loam," coined 1823 by German mineralogist Karl Cäsar von Leonhard (1779-1862) from German Löss "yellowish-gray soil," from Swiss German lösch (adj.) "loose" (cf. German los; see loose). Related: Loessial.

Online Etymology Dictionary, © 2010 Douglas Harper

loess in Science


[lōəs, lĕs, lŭs]

A very fine grained silt or clay, thought to have formed as the result of grinding by glaciers and to have been deposited by the wind. Most loess is believed to have originated during the Pleistocene Epoch from areas of land covered by glaciers and from desert surfaces.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.